Grinding machine



June 27, 1933. H. w. MILLER GRINDING MACHINE Filed Aug. 29, 1931 5 SheelzS-Sheel l mh 1 W .w mi Qxfm MW ,9v e l@ u 31a/vento@ 'ary WM'ZZer atto/mug June 27, 1933. Hn w, M|| ER 1,916,063

GRINDING MACHINE Filed Aug. 29, 1931 5 Sheets-Sheet 2 bten/mg `lune 27, 1933.

H. W. MILLER GRINDING MACHINE Filed Aug. 29, 1931 5 Sheets-Sheet 3 June 27, 1933. H, w. MILLER GRINDING MACHINE Filed Aug. 29, 1951 5 Sheets-Sheet 4 June 27, 1933'. H, w MILLER GRINDING MACHINE Filed Aug. 29, 1931 5 Sheets-Sheet 5 mento@ WMZ/w Patented .lune 27, 1933 BARRY W. MILLER, F LANCASTER, PENNSYLVANIA.

GBINDING MACHINE Application led\Aug11st 29, 1931.

My invention relates to grinding machines and especially to grinding machines particularly designed for sharpening the curved blades of lawn mowers.

The object of my invention is to provide in a grinding machine for sharpening lawnv mower blades, improved means for driving and reciprocating the grinding tool. A fur- Vther object of my invention is to provide, in 0 a device of the class mentioned having a reciprocating carriage for the grinding element, a single driving element carried by the carriage and geared to drive the driving element and to reciprocate the carriage. A

further vobject of my invention is to provide improved means for reversing the carriage at the end of each reciprocation. A further object of my invention is to provide safety means for preventing the carriage from traveling too far in either direction and at the same time to maintain the reciprocating mechanism in operative geared connection.

A further object of my invention is to pro- F vide improved carriage reversing mechanism 2Q which shan be easily actuated and of Such construction as to prevent locking or jamming of the gears. A further object of my invention is to provide improved-means for maintaining the mower blade in proper relation to the grinding tool. A further object of my invention is to provide, in a device of the class mentioned, means for maintaining the mower blade in proper relation to the grinding tool, said means being adjustable, vertically, horizontally and angularly to accommodate various types and sizes of mowers. A further object of my invention is to provide, in a machine of the class mentioned, means for maintaining the blade in proper relation to the grinding tool and of such construction that blades may be sharpcned when so badly worn as to project but slightly beyond their supporting arms. Other objects will appear hereinafter.

With these objects in view my invention consists generally in a grinding tool comprising a reciprocatory carriage mounted upon ways, a rack bar paralleling said ways, a grinding tool on said carriage, a motor o mounted onV said carriage, gearing connect- Serial No. 560,173.

ing the motor and grinding tool and a train of gearing connecting the motor and said rack bar for reciprocating the carriage, whereby the carriage is reciprocated at a y sldw speed and the grinding tool-driven at a L 5 high speed, simultaneously from the same motor. My invention further consists in a device as above mentioned, in which the train of gears for reciprocating the carriage includes a pair of oppositely rotated pinions CJ adapted to be alternately engaged with a pinion in mesh with the rack for imparting reciprocatory motion to the carriage. VMy invention further consists in a' device as above mentioned, including a worm gear connection between the motor shaft and the train of gears for stepping down the speed of the carriage reciprocating gearing. My invention further consists in a device as mentioned in combination with adjustable means for automatically shifting the rack engaging pinions at the end of each reciprocation.

My invention further consists in a device ofthe class mentioned including a reciprocatory carriage; a rack and pinion for reciprocat-ing the same, in which the rack is floating, that is, mounted to have a limited longitudinal movement, and of such length as to be disengaged bythe pinions at the extreme limits of movements; and resilient means for returning the rack bar. to position to engage with the pinion to facilitate reversal of travel of the carriage. My invention further consists in a device ofthe class under consideration including a reciprocatory carriage, a rack, a pinion on the carriage meshing with said rack, a pair of oppositely driven pinions mounted on a pivoted member carried by said carriage and means ior automatically shifting said member at the end of each reciprocation of the carriage to mesh the alternate pinions with the first said pinion, thevdirection of rotation of said pinions and their relative positions being Asuch as to maintain the same in mesh. My invention further consists in a device as above stated further characterized by stops to limit the movement of the shifting gears to prevent the same from becoming jammed.

My invention further consists in a grind- 10 ing tool of the class mentioned including the grinding wheel and means for maintaining the lawn mowerblade in proper relation thereto, said means comprising a fixed roller and a roller mounted upon a swinging arm, therollers being adapted to grip the blade upon opposite sides, and the last mentioned roller being adapted to be swung upwardly out of operative osition when the tool is operating upon a adly worn mower blade, so that the roller will not engage the reel arm which supports the blade. My invention further consists in a blade guiding device as mentioned, which may be vertically, horizontally and angularly adjusted with relation to the grinding tool so as to accommodate the device to mowers of diiferent sizes. M invention further consist-s in various detalls of construction and arrangements of parts, all as will be fully -described hereinafter and particularly pointed out in the claims.

M invention will be more readily understoo by reference to the accompanying drawings, forming a part of this specification and in whichl Figure 1 is a front elevation of a lawn mower grinding machine embodying my invention,

Fig. 2 is a transverse section of the same on substantially the line 2-2 of Fig. 1 and illustrated upon an enlarged scale, the vertical elements of the frame and adjacent parts being broken away,

Fig. 3 is a plan view of the device on an enlarged scale, partly broken away,

Figs. 4 and 5 are detail views illustrating the construction and manner of mounting the floating rack bar at one end,

Fig. 6 is a detail View illustrating the other end of the rack bar and associated parts,

Fig. 7 is a side elevation of the grinding wheel and associated parts illustrated upon a much enlarged scale,

Fig. 8 is a top plan view of the same,

Fig. 9 is a section on substantially the line 9-9 of Fig. 7, and

Fig. 10 is a detail of a portion of the work rest.

The device comprises broadly a rigid frame which includes the ways for a reciprocatory carriage; a reciprocatory carriage mounted on the ways, and carrying a motor, a grinding tool, and carriage driving gearing; a rack bar mounted upon the frame and associated with said gearing; adjustable means for automatically shifting the gearing; and adjustable work holding means.

The frame comprises a pair of similar skeleton end members 1 and 2 respectively connected at their lower ends by a pair of transverse members 3 and at their upper end by a longitudinally disposed bar 4. The bar 4 constitutes ways for the reciprocatory carriage hereinafter described, and in order that said carriage may be firmly supported on the single member 4, said member is made rectangular in cross section and arranged on its diagonal axis as'clearly illustrated in Fig. 2 of the drawings. The ends of the member 4 are rigidly secured to the upper portion of the frame in any preferred manner.

The reciprocatory carriage per se comprises upper and lower plates 5 and 6 secured together as by bolts 7 and recessed in their adjacent faces, as at 8, to snugly fit the wa s 4. 9 indicates a motor casing secured to t e underface of the carriage. This casing is provided on its upper portion with front and rear securing flanges 10 and 11 respectively,

and the under member 6 of the carriage is formed with depending portions 12 and 13 to which said anges are respectively secured.

14 indicates the motor shaft having suitable bearings in the motor casing and provided at one end with a worm 15 which meshes with a worm gear 416 in a shaft 17. The upper end of the shaft 17 is provided with a pinion 18 which is connected through a train of gears, hereinafter described, to a gear 19 which meshes with a rack 20 on a rack bar 2l mounted on the frame of the machine in a manner hereinafter described.

This gearing and rack are for the purpose of reciprocating the carriage on its ways. The worm and gear, 15-16, are arranged in a housing 22 at one end of the motor casing 9, and mounted upon the upper end of the housing 22 is a rearwardly extending fixed arm 23. Upon the end of said arm is secured a slide block 24, which engages the rear portion of the rack bar 21 and maintains a fixed d'istance between t-he rack bar and the shaft 1 Pivotally mounted on the upper face of the arm 23 is a bell crank lever 25 having a long arm 26 and a short arm 27, upon the ends of which are mounted pinions 28 and 29 respectively. The shaft 17 forms a pivot pin for the bell crank lever and by shifting said lever either of the pinions 28 or 29 may be brought into mesh with the gear 19. The pinion 29 is constantly in mesh with the pinion 18, whereas an idler 30 is interposed between the pinions 18 and 28. By this arrangement, the pinions 28 and 29 are constantly driven in opposite directions, so that by shifting the same to alternately engage the gear 19, the carriage will be driven in opposite directions. The arms 26 and 27 are of sufiicient length whereby the teeth of the pinions 28 and 29 may be easily brought into and out of mesh with the gear 19. The bell crank lever 25 is provided with a forwardly extended arm 31, by means of which said lever and the pinions carried thereby may be shifted, either by hand or automatically in a manner hereinafter described.

In order to prevent injury to the motor, the

a transverse shaft 37` gearing, or other portions of the machine, should the gears not be properly shifted at the end of thetravel of the carriage, AI provide safety means forstopping the travel of the carriage and this includes means whereby the rack 20 and gear 19 are maintained in operative relation so as to return the carriage when the gears ar'e shifted. To this end, the rack bar 21 is supported at its ends in housings 32 -and 33 arranged at the opposite ends,A respectively, has limited longitudinal movement. The rack 20 is of but sutlicient length to give the maximum desired travel to the carriage, so that when the carriage reaches the extreme limit of its'normal movement in either direction. the gear 19 passes slightly beyond the teeth of the rack. Without provisions being made to maintain the rack and gear in operat've position` this travelling o the gear beyond the ends of the rack would prevent the return of the carriage in the opposite direction without considerable diiiiculty in again getting the rack and pinion into proper engagement. In order to overcome this objection and maintain the rack and pinion in. operative relation,-I provide means for returning the rack into engagement withthe gear after the gear has passed beyondthe ends of. said rack.- To this end, I providef adjacent each end of the rack, a plunger 34, slidably mounted in a lug 35 on the rack bar 31. interposed between the lug 35 and the head of the plunger 34 Ais a spring 36. In operation, when the carriage is travelling in one direction, the gear 19 will force the rack in the opposite direction for the limited movement of the rack bar, until the end of the bar engages a stop, such as the adjacent portion of the frame 1 or 2. When the gear 19 passes from the opposite ends of the rack, the arm 23 on thegear housing engages the plunger V34 and forces the same toward the lug 35 against the tension of the spring 36. rlhe spring 36 will then move the rack b ar and rack so as to maintain the end of the rack in operative relation with the gear 19 until the direction of rotation of said gear is changed by 'shifting the pinions 28 and 29.

In order to automatically shift the gears and adjust the length of travel of the carriage to suit the work, I provide adjustable stop members 36 arranged in the path of the arm 31. These stop members are .preferably depending elements loosely mounted on and held in adjusted position by collars 38, adjustably fixed to the shaft 37 by set screws 39.

The opposite end of. the motor shaft 14 from the worm 15 is provided with a spur gear 40, meshing with a pinion 41 on the shaft 42 of the grinding wheel 43. lThe gear 40 arid pinion 41 are proportioned to step u t e be seen that the single motor shaft is geared of `the machine, and

. p seth speed of the grind wheel 43. It will thus to drive the grinding wheel at a high speed and also geared to drlve the carriage reciprocating gearing at a low speed.

The mower is supported below the grinding wheel in the following manner. At the rear of the machine is a transverse longitudinal bar 44 upon which is slidably mounted a sleeve 45 havingan upwardly projecting supporting. lug 46 provided with a recess 47 in which the wooden roller of the lawn mower is adapted to rest at substantially its longitudinal center..` The bar 44 is supported adjacent its ends by depending rods 48 which extends through apertures in the bar and are threaded as shown clearly in Figs. 1 and 2 to receive thumb nuts 49 upon which the -bar 44 rests. By turning the thumb nuts 49, the height to the bar and the roller rest thereon may be adjusted. At each end of the device, are forwardl extending arms 50, the inner ends of which, are provided with sleeves 51, whereby they are shdably mounted upon vertical ways 52. The arms are also provided with sleeves 53 throughwhich are threaded vertical shafts 54. These shafts have the'r lower ends mounted at the base of the franie and their upper ends are journalled in the top of the frame, extended therethrough and equipped with bevel gears 55, which mesh with bevel gears 56 on the longitudinal shaft 37. The end of the shaft 37 is provided with a hand crank 57. It is obvious that by turning the shaft 37, the arms 50 will be simultaneously raised or lowered. Mounted upon each of the arms 50 is a 'slide 58 and the slides 58 are connected by horizontal members 59 members59 are a ing sleeves 61 into which telescope rest members 62 adapted to support the cross bar of the mower, said members being recessed at their upper ends as at `l63 for'this purpose. The rest members 62 are adjusted vertically by means of a screw 64 threaded through the llower end of the sleeve 61,. The lower ends of the Sleeve 6l are reduced in diameter to extend through the slot and are threaded to receive a nut 65 for clamping the sleeve I in adjusted position on the members 59. By

this construction, it is obvious that the mower after having been placed on the rest 46 and 62 may be nicely adjusted into proper relation to the grinding wheel 43.

The upper portion of the grind wheel 43 is covered bya suitable guard. This comprises a hollow substantiallyV semi-circular member 66, which is mounted upon the outer face of the gear housing V67 which is provided on the end of the motor housing 9 for the gearing 40, 41. To this end, the gear housing is formed with a lug 68, and the guard 66 witha similar lug 69, which are secured toer in any preferred manner as by bolts 70.

One of the features of thevpresent invention is improved means for maintaining the Vspaced to provide a slot 60. Mounted on the pair of upwardly project- A prises broadly a pair of rollers mounted' vupon each side of the grinding wheel adjacent its periphery, each pair being mounted upon a spring arm, and the outer roller of cach pair being also mounted upon a pivoted member whereby it may be swung toward and from a companion roller. The rollers of each pair are adapted to engage opposite sides of the blade being sharpened and the pivotally mounted roller is held in yielding contact therewith by a suitable spring; and means are provided for adjusting the movement of this roller towardthe fixed companion roller. Means arealso provided for adjusting each pair of rollers ver# tically, horizontally and angularly with relation to the grinding wheel. As the pairs of rollers on each side of the grinding wheel and their associated parts are substantially identical, the description of one pair will suiiice; it being understood that in practice one pair of rollers is set forwardly with relation to the other according to the degree of curve of the mower blade.

Referring to the drawings, particularly Figs. 7, 8 and 9, 71 indicates what will be called the tixed roller, and 72 the pivotally mounted roller. The fixed `roller is of conical form and mounted on a spring 73, which is angularly disposed so as-.to bring the outer portion of the roller into a substantially vertical position. The arm 73 is provided at its end with a bracket 74 in which the upper end of the roller axel is mounted, the lower end of the axel being secured in the end of the arm 73. The bracket 74 is formed with an upwardly extending disk portion 75 and a rearwardly extending arm 76 having an offset lug 77. Pivotally mounted as at 78 on the disk 75 is a similar disk 79 having a substantially tangentially extending arm 80, upon the end of which is mounted the roller 72. A spring 81 -interposed between the arm and the lugs 77 tends to normally draw the roller 72 toward the roller 71. A setscrew 82 threaded through the arm 80 impinges against the end ot the bracket 74 to regulate the space between the rollers. After the mower has been placed in proper position upon the supports 47 and 63, one of the blades is turned under the arm 73 in the direct-ion of the arrow 83 in Fig. 7. The blade will engage the underface of the end of the spring arm 73, raising the same and the rollers until the blade slips between the rollers, when the resiliency of the arm 73 will return the rollers to normal position, clamping the blade between them. Sometimes the mower blade is so badly worn that its edge extends but a slight distance beyond the arm of the reel.v At such times, the blade supporting arm of the reel would lie in the path of the roller. When such is the case,

the mower is reversed on its supports so as to present'said arms toward the front of Vthe machine, and the arm 8O with the roller In order to permit proper adjustment ot the rollers for such purpose as mentioned in the last paragraph, and for mowers of different types and sizes, the spring arm 7 3 is mounted upon a block 84 in such a manner as to be longitudinally (horizontally) adjustable thereon and the block carrying said spring arm is mounted for vertical adjustment. Provision is also made for angular adjustment of the arm 73. The upper end of the spring arm is rebent, forming a portion 85, which is slotted as at 86 to receive a bolt 87, tapped into the block 84.' A strap member 88 isixed to the portion 85 and has an upturned rear end 89 in which is swiveled a screw 90, said screw being tapped into the block 84. It is obvious that by loosening the bolt 87 and turning the screw 90, the spring arm 73 and the rollers carried thereby will be horizontally adjusted, forwardly or rearwardly with relation to the grinding wheel, after which the bolt 87 is tightened to secure the same in adjusted position. The front end of the member 88 is bent forwardly and downwardly, and extending from the same is a rod 91, the end ot which is threaded and extended through the arm 73. A nut 92 threaded thereon impinges against the bottom of the arm and by turning said nut, the arm 73 may be adjusted angularly with relation to the horizontal. The block 84 has an upwardly projecting arm 93, which slides vertically between parallel ribs 66 on the side of the guard 66. A bolt 94 extends through the arm 93 and a slot 95 in the guard 66 and is provided with a thumb nut 96, whereby the block may be clamped in vertically adjustable position. A vertically disposed screw 97 extends through a lug 98 on the guard 66 and is tapped into the arm 93. A sleeve 99 is interposed between the lug 98 and the head 100 of the screw to bring the head well above the guard. It is obvious that when the thumb nut 9G is loosened, the block 84 may be readily adjusted by the screw 99. When properly adjusted vertically the clamp screw 96 is tightened to hold it in position.

It should be noted that the single motor mounted von the carr'age is used for simultaneously driving the carriage and operating the grinding tool, the driving or reciprocation of the carriage being at a relatively slow speed and the grinding tool being driven at a relatively high speed. This is aecomplished through the gearing above described connecting the motor shaft with the rack and pinion, and the step up gearing connecting the same motor shaft with the shaft of the grinding tool.

It should also be noted that with the particular gearing described as connecting the motor with the rack, that the direction of rotation of the gears will tend to hold the same in their operative relation, and the arms 26 and 27 of the bell crank lever 25 are provided with stops 26 and 27 to limit the throw of the arms and prevent jamming or locking of the gears. The lengths of these arms are also such as to facilitate throwing the gears into and out of mesh without becoming locked.

Iclaim:

1. In a grinding tool, a reciprocatory carriage, a rack. a gear on said carriage meshing with said rack, a bell crank lever pivoted on the carriage, pinions on the arms of said lever and adapted to be alternately engaged with said gear, speed reducing gearingr connecting said motor and said pinions, and speed increasing mechanism connecting said motor and said grinding tool, substantially as described.

2. A device as set forth in claim 1 in combination with means for shifting the bell crank lever at the end of travel of the carriage in each direction and means for limiting the throw of said lever, substantially as described.

3. In a device of the class described, a reciprocatory carriage, ways for said carriage, a rack paralleling said ways, a motor and motor casing mounted upon the carriage, gear housing at one end of said casing, a grinding tool supported on said housing, speed step up gearing arranged in said housing and connecting the motor and driving tool, a gear housing at the opposite end of said casing, a shaft mounted in said housing, an arm extending from said housing, mans on said arm engaging the back of the rack bar, a pinion on said arm meshing with the rack, a bell crank lever pivotally mounted on said arm and including a pair of angularly disposed arms, pinions mounted on said arms and adapted to be alternately engaged with said gear upon shifting of the lever, and gearing connecting the last mentioned shaft and said pinions for driving said pinions in opposite directions, substantially as described.

4. A device as set forth in claim 3 in combination with adjustable means for shifting said bell crank lever, substantially as described.

5. In a device of the class described, a reciprocatory carriage, a grinding tool carried thereby, a rack, a pinion carried by said carriage and'meshing with saidrack, means for driving said pinion in opposite directions to reciprocate the carriage, said rack bar having limited longitudinal movement and resilient means carried by the rack bar and adapted to be engaged by a portion of the carriage as the pinion reaches the end of the rack and adapted to maintain operative relation between the rack and pinion, substantially as described.

6. In a device of the class described, a reciprocating carriage, a grinding tool' on said carriage, means for supporting a lawn mower with its rotary blades .in operative relation to said grinding tool, blade guiding means adapted to engage the blade and maintain the same in operative relation vto the tool as the carriage is reciprocated, said blade guiding means comprising a pair of gripping rollers engaging the blade upon opposite sides, one of said rollers being swingingly mounted and normally projecting below the level of the other roller, substantially as described.

7. A device as set forth in claim 6 further characterized by a spring arm supporting said rollers.

8. In a lawn mower sharpening device, a reciprocating carriage, a grinding tool mounted on said, carriage and means for maintaining a lawn mower blade in position to be operated upon said grinding tool, said means comprising a fixed roller and a swinging roller at the side ofthe grinding tool and adapted to hold the blade between them, and means for adjusting said rollers horizontally, vertically and angularly with relation to the tool, substantially as described.

9. A device as set forth in claim 8 in combination with means for maintaining the swinging roller in or out of operative relation with the iXed roller, substantially as described.

10. In a device of the class described, a reciprocatory carriage` a grinding tool mounted thereon and means for driving said tool, in combination with means for maintaining a lawn mower blade in proper relation to the grinding tool, said means comprising an angularly disposed spring arm, a fixed roller on the end of said arm, a clamping roller pivotally mounted on said arm, and mea-ns for maintaining the swinging roller in either operative or inoperative relation to the fixed roller, substantially as described.

11. A device as set forth in claim 10 in combination with means `for adjusting the` angularity of the spring arm, substantially as described.

l2. A device as set forth in claim 10 further charaeterized by a block upon which said spring arm is mounted, a slot and bolt connection between said spring arm and block providing horizontally .adjusting 14. A device as set forthin claim 10 further characterized by a block upon which the s ring arm is mounted, there being a slot and olt connection between said block and spring arm, means for vertically adjusting the block and means for angularly adjusting said arms, substantially as described.

In testimony whereof I have signed my name to this specification.

. HARRY W. MILLER. 

